Termination-of-resuscitation rule in the emergency department for patients with initial pulseless electrical activity after out-of-hospital cardiac arrest

Abstract

Abstract Background/Introduction In several Asian countries including Japan, emergency medical service (EMS) providers are prohibited from performing field termination-of-resuscitation (TOR) in patients with refractory out-of-hospital cardiac arrest (OHCA). In 2022, we developed a TOR rule in the emergency department for patients with initial asystole after refractory OHCA, which includes three criteria: unwitnessed arrest, EMS-initiated cardiopulmonary resuscitation (CPR) duration was more than 20 min, and there was no prehospital return of spontaneous circulation (ROSC). However, until now a TOR rule in the emergency department for patients with initial pulseless electrical activity (PEA) has not been developed. Purpose This study aimed to develop and validate a TOR rule in the emergency department for patients with initial PEA after refractory OHCA. Methods We analysed the records of 137,230 adult patients (≥18 years-old) with initial PEA from the nationwide all-Japan Utstein registry from 2016 to 2020. Patients were divided into two groups: development (n=109,642, 2016 to 2019) and validation (n=27,588, 2020). The primary outcome measures were specificity, false positive rate (FPR), and positive predictive value (PPV) of the TOR rule for patients with initial PEA in the emergency department for predicting 1-month mortality. Using recursive partitioning analysis, we developed a new TOR rule for patients with initial PEA after OHCA. Results The overall 1-month survival rate of the participants was 7.4% (95% confidence interval [CI], 7.2–7.5%). Recursive partitioning analysis for the development group in predicting 1-month mortality revealed that a TOR rule for patients with PEA could be defined if patients with OHCA met all the following four criteria immediately after hospital arrival: (1) unwitnessed arrest by any laypersons, (2) EMS-initiated CPR duration more than 20 min, (3) no prehospital ROSC, and (4) age greater than or equal to 80 years. The specificity, FPR, and PPV of the rule for predicting 1-month mortality were 99.1% (95% CI, 98.9–99.3%), 0.87% (95% CI, 0.69–1.09%), and 99.2% (95% CI, 98.9–99.3%), respectively. The proportion of patients who fulfilled the rule and the area under the receiver operating curve (AUC) was 7.8% (95% CI, 7.7–8.0%), and 0.80 (95% CI, 0.79–0.80), respectively. In the validation group, the specificity, FPR, PPV, proportion of patients who met the rule, and AUC were 99.1% (95% CI, 98.5–99.4%), 0.93% (95% CI, 0.58–1.49%), 99.3% (95% CI, 98.8–99.5%), 8.3% (95% CI, 8.0–8.6%), and 0.789 (95% CI, 0.775–0.797), respectively. Conclusions We developed and validated a TOR rule in the emergency department for patients with initial PEA after OHCA. The rule includes four criteria (unwitnessed arrest, EMS-initiated CPR duration was more than 20 min, no prehospital ROSC, and age was greater than or equal to 80 years) with a more than 99% predictor of 1-month mortality.